The Met Office has issued a red warning for extreme heat across parts of England and Wales, a step it has taken only once before. The alert underlines the severity of a heatwave that forecasters say is already building and is expected to intensify sharply over the coming days, bringing temperatures rarely seen in the United Kingdom.
According to the forecast, temperatures could reach around 37C in southern England on Tuesday. By Wednesday and Thursday they are expected to climb further, to about 39C, with forecasters warning there is a chance the readings could go even higher as the hottest part of the spell arrives in the middle of the week.
The last time the country saw heat on this scale was in July 2022, when the UK recorded its hottest ever day at 40.3C. That episode brought consequences that went well beyond discomfort, including unprecedented wildfires, infrastructure that struggled to cope and a series of heat-related health impacts across the country.
This time, forecasters say the record may not be broken, and recent rainfall means wildfires may be less of a threat than they were three years ago. Even so, the risk to people's health is expected to be significant, which is the central reason the Met Office moved to its most serious level of warning rather than a lower alert.
Part of the danger lies in the lack of relief after dark. Overnight temperatures are forecast to stay around 20C across parts of England, and humidity is expected to be high. Warm nights make it harder for the body to recover from the heat of the day, raising the strain on vulnerable people in particular.
A red heat warning signals a risk to life that extends even to otherwise healthy members of the population, not only those who are already vulnerable. The Met Office has cautioned that the effects reach beyond health and social care, with potential disruption to transport, food, water and energy supplies, businesses and even mobile phone networks.
With the warning now in place, attention turns to how communities and services across England and Wales cope as the temperatures peak. Authorities are urging people to take the heat seriously through the most intense days of the spell, treating the red alert as a clear signal that conditions could become dangerous rather than merely uncomfortable.